Simultaneous detection of influenza A, B and respiratory syncytial virus in wastewater samples by one-step multiplex RT-ddPCR assay.

BACKGROUND: After the occurrence of the COVID-19 pandemic, detection of other disseminated respiratory viruses using highly sensitive molecular methods was declared essential for monitoring the spread of health-threatening viruses in communities. The development of multiplex molecular assays are essential for the simultaneous detection of such viruses even at low concentrations. In the present study, a highly sensitive and specific multiplex one-step droplet digital PCR (RT-ddPCR) assay was developed for the simultaneous detection and absolute quantification of influenza A (IAV), influenza B (IBV), respiratory syncytial virus (RSV), and beta-2-microglobulin transcript as an endogenous internal control (IC B2M). RESULTS: The assay was first evaluated for analytical sensitivity and specificity, linearity, reproducibility, and recovery rates with excellent performance characteristics and then applied to 37 wastewater samples previously evaluated with commercially available and in-house quantitative real-time reverse transcription PCR (RT-qPCR) assays. IAV was detected in 16/37 (43%), IBV in 19/37 (51%), and RSV in 10/37 (27%) of the wastewater samples. Direct comparison of the developed assay with real-time RT-qPCR assays showed statistically significant high agreement in the detection of IAV (kappa Cohen's correlation coefficient: 0.834, p = 0.001) and RSV (kappa: 0.773, p = 0.001) viruses between the two assays, while the results for the detection of IBV (kappa: 0.355, p = 0.27) showed good agreement without statistical significance. CONCLUSIONS: Overall, the developed one-step multiplex ddPCR assay is cost-effective, highly sensitive and specific, and can simultaneously detect three common respiratory viruses in the complex matrix of wastewater samples even at low concentrations. Due to its high sensitivity and resistance to PCR inhibitors, the developed assay could be further used as an early warning system for wastewater monitoring.

Assessment of effectiveness and impact of universal prophylaxis with nirsevimab for prevention of hospitalizations due to respiratory syncytial virus in infants. The NIRSE-GAL study protocol.

Nirsevimab has been recently licensed for universal RSV prophylaxis in infants. NIRSE-GAL is a three-year population-based study initiated in Galicia in September 2023. It aims to evaluate nirsevimab effectiveness against RSV-related hospitalizations lower respiratory tract infections (LRTI), severe RSV, all-cause LRTI, and all-cause hospitalization. NIRSE-GAL also aims to estimate nirsevimab impact on primary healthcare use in the short and mid-term, children's wheezing and asthma, and medical prescriptions for RSV. The immunization campaigns will be scheduled based on the expected start week for the RSV season and will last the whole season. Immunization will be offered to: i) infants born during the campaign (seasonal), ii) infants < 6 months at the start of the campaign (catch-up), and iii) infants with high-risk factors, aged 6-24 months at the start of the campaign (high-risk). The follow-up period will start: i) the immunization date for all immunized infants, ii) the start of the campaign, for the non-immunized catch-up or high-risk groups, or iii) the birthdate for the non-immunized seasonal group. Infants will be followed up until outcome occurrence, death, or end of study. Nirsevimab effectiveness will be estimated using Poisson and Cox regression models. Sensitivity and stratified analyses will be undertaken. The number of averted cases and the number needed to immunize will be estimated. Immunization failure and nirsevimab safety will be monitored. NIRSE-GAL was approved by the ethics committee of Galicia (CEIC 2023-377) and registered in ClinicalTrials.gov (ID: NCT06180993). Findings will be mainly shared via peer-reviewed publications and scientific conferences.

Estimated Impact of Nirsevimab on the Incidence of Respiratory Syncytial Virus Infections Requiring Hospital Admission in Children < 1 Year, Weeks 40, 2023, to 8, 2024, Spain.

BACKGROUND: Data from the sentinel surveillance system of severe acute respiratory infections in Spain were used to estimate the impact of administration of nirsevimab to children born from 1 April 2023 onwards. METHODS: Estimated RSV hospitalisations in < 1-year-olds during weeks 40, 2023, to 8, 2024, were compared to the number that would be expected after accounting for the background change in RSV circulation in the 2023/24 season, compared to 2022/23. RESULTS: We estimated 9364-9875 RSV hospitalisations less than expected, corresponding to a 74%-75% reduction.

The Role of Human Mobility Flow in the Region-to-Region Spread of Respiratory Syncytial Virus Infection among Infants: An Infographic Analysis.

The region-to-region spread of human infectious diseases is considered to be dependent on the human mobility flow (HMF). However, it has been hard to obtain the evidence for this. Since the onset of the coronavirus disease 2019 (COVID-19) pandemic in Japan 2020, the government has enforced countermeasures against COVID-19 nationwide, namely the restriction of personal travelling, universal masking, and hand hygiene. As a result, the spread of acute respiratory infections had been effectively controlled. However, COVID-19 as well as pediatric respiratory syncytial virus (RSV) infections were not well-controlled. The region-to-region spread of pediatric RSV infections in 2020-2021 was recognizable unlike those in 2018 and 2019. In this study, we investigated the correlation between the trend of regional reports of the pediatric RSV infections and the HMF based on cellular phone signal data. Upon closer examination of both epidemiological trend and HMF data, the spread of pediatric RSV infection from one region to another was logically explained by HMF, which would serve as the evidence of the dependence of regional transmission on HMF. This is the first solid evidence where this correlation has been clearly observed for the common respiratory infections. While social implementation of infection control measures has successfully suppressed the droplet-mediated respiratory infections, such as influenza, but not the airborne infections, it was suggested that the aerosol transmission and adult asymptomatic carrier were involved in the transmission of RSV akin to COVID-19.

Estimating the Undetected Burden of Respiratory Syncytial Virus Hospitalizations in Adults Through Capture-Recapture Methods.

INTRODUCTION: Traditional surveillance systems may underestimate the burden caused by respiratory syncytial virus (RSV). Capture-recapture methods provide alternatives for estimating the number of RSV-related hospitalizations in a population. METHODS: Capture-recapture methods were used to estimate the number of RSV-related hospitalizations in adults in Middle Tennessee from two independent hospitalization surveillance systems during consecutive respiratory seasons from 2016-2017 to 2019-2020. Data from the Hospitalized Adult Influenza Vaccine Effectiveness Network (HAIVEN) and the Emerging Infections Program (EIP) were used. Annual RSV hospitalization rates were calculated using the capture-recapture estimates weighted by hospitals' market share divided by the corresponding census population. RESULTS: Using capture-recapture methods, the estimated overall adult hospitalization rates varied from 8.3 (95% CI: 5.9-15.4) RSV-related hospitalizations per 10,000 persons during the 2016-2017 season to 28.4 (95% CI: 18.2-59.0) hospitalizations per 10,000 persons in the 2019-2020 season. The proportion of hospitalizations that HAIVEN determined ranged from 8.7% to 36.7% of the total capture-recapture estimated hospitalization, whereas EIP detected 23.5% to 52.7% of the total capture-recapture estimated hospitalizations. CONCLUSION: Capture-recapture estimates showed that individual traditional surveillance systems underestimated the hospitalization burden in adults. Using capture-recapture allows for a more comprehensive estimate of RSV hospitalizations.

Assessment of Illness Severity in Adults Hospitalized With Acute Respiratory Tract Infection due to Influenza, Respiratory Syncytial Virus, or Human Metapneumovirus.

BACKGROUND: Influenza, respiratory syncytial virus (RSV), and human metapneumovirus (hMPV) are common respiratory viruses causing similar symptoms. Optimal tools to assess illness severity for these viruses have not been defined. Using the Hospitalized Acute Respiratory Tract Infection (HARTI) study data, we report symptom severity by clinician-rated clinical severity scores (CSS) in adults with influenza, RSV, or hMPV and correlations between CSS and patient-reported outcomes (PROs). METHODS: HARTI was a global epidemiologic study in adults hospitalized with acute respiratory tract infections. Patients were assessed at enrollment within 24 h of admission with CSS and twice during hospitalization with CSS, Respiratory Infection Intensity and Impact Questionnaire™ (RiiQ™), and EQ-5D-5L. Data were summarized descriptively, stratified by pathogen and baseline and hospitalization characteristics. Domain (general, upper respiratory, and lower respiratory) and sign/symptom subscores are presented for CSS; sign/symptom subscores are presented for RiiQ™ results. RESULTS: Data from 635 patients with influenza, 248 with RSV, and 107 with hMPV were included. At enrollment, total CSS and general and lower respiratory signs/symptoms (LRS) scores were higher for RSV and hMPV than influenza. Between-pathogen differences were greatest for LRS scores. Dyspnea, rales/rhonchi, wheezing, and shortness of breath scores trended higher for RSV and hMPV than influenza. RiiQ™ scores for cough, fatigue, and short of breath were strongly correlated with corresponding clinician-rated symptoms. CONCLUSIONS: These findings support the use of PROs (e.g., the RiiQ™) correlating with clinician assessments to gauge patient well-being and aid patient management by accurately assessing respiratory illness severity due to RSV, hMPV, or influenza.

Coinfection with respiratory syncytial virus and rhinovirus increases IFN-λ1 and CXCL10 expression in human primary bronchial epithelial cells.

Acute respiratory tract infection (ARTI) is common in all age groups, especially in children and the elderly. About 85% of children who present with bronchiolitis are infected with respiratory syncytial virus (RSV); however, nearly one-third are coinfected with another respiratory virus, such as human rhinovirus (HRV). Therefore, it is necessary to explore the immune response to coinfection to better understand the molecular and cellular pathways involving virus-virus interactions that might be modulated by innate immunity and additional host cell response mechanisms. This study aims to investigate the host innate immune response against RSV-HRV coinfection compared with monoinfection. Human primary bronchial/tracheal epithelial cells (HPECs) were infected with RSV, HRV, or coinfected with both viruses, and the infected cells were collected at 48 and 72 hours. Gene expression profiles of IL-6, CCL5, TNF-α, IFN-ß, IFN-λ1, CXCL10, IL-10, IL-13, IRF3, and IRF7 were investigated using real-time quantitative PCR, which revealed that RSV-infected cells exhibited increased expression of IL-10, whereas HRV infection increased the expression of CXCL10, IL-10, and CCL5. IFN-λ1 and CXCL10 expression was significantly different between the coinfection and monoinfection groups. In conclusion, our study revealed that two important cytokines, IFN-λ1 and CXCL10, exhibited increased expression during coinfection.

m6A Reader YTHDC1 Impairs Respiratory Syncytial Virus Infection by Downregulating Membrane CX3CR1 Expression.

Respiratory syncytial virus (RSV) is the most prevalent cause of acute lower respiratory infection in young children. Currently, the first RSV vaccines are approved by the FDA. Recently, N6-methyladenosine (m6A) RNA methylation has been implicated in the regulation of the viral life cycle and replication of many viruses, including RSV. m6A methylation of RSV RNA has been demonstrated to promote replication and prevent anti-viral immune responses by the host. Whether m6A is also involved in viral entry and whether m6A can also affect RSV infection via different mechanisms than methylation of viral RNA is poorly understood. Here, we identify m6A reader YTH domain-containing protein 1 (YTHDC1) as a novel negative regulator of RSV infection. We demonstrate that YTHDC1 abrogates RSV infection by reducing the expression of RSV entry receptor CX3C motif chemokine receptor 1 (CX3CR1) on the cell surface of lung epithelial cells. Altogether, these data reveal a novel role for m6A methylation and YTHDC1 in the viral entry of RSV. These findings may contribute to the development of novel treatment options to control RSV infection.

Intranasal respiratory syncytial virus vaccine attenuated by codon-pair deoptimization of seven open reading frames is genetically stable and elicits mucosal and systemic immunity and protection against challenge virus replication in hamsters.

Respiratory syncytial virus (RSV) is the most important viral agent of severe pediatric respiratory illness worldwide, but there is no approved pediatric vaccine. Here, we describe the development of the live-attenuated RSV vaccine candidate Min AL as well as engineered derivatives. Min AL was attenuated by codon-pair deoptimization (CPD) of seven of the 11 RSV open reading frames (ORFs) (NS1, NS2, N, P, M, SH and L; 2,073 silent nucleotide substitutions in total). Min AL replicated efficiently in vitro at the permissive temperature of 32°C but was highly temperature sensitive (shut-off temperature of 36°C). When serially passaged at increasing temperatures, Min AL retained greater temperature sensitivity compared to previous candidates with fewer CPD ORFs. However, whole-genome deep-sequencing of passaged Min AL revealed mutations throughout its genome, most commonly missense mutations in the polymerase cofactor P and anti-termination transcription factor M2-1 (the latter was not CPD). Reintroduction of selected mutations into Min AL partially rescued its replication in vitro at temperatures up to 40°C, confirming their compensatory effect. These mutations restored the accumulation of positive-sense RNAs to wild-type (wt) RSV levels, suggesting increased activity by the viral transcriptase, whereas viral protein expression, RNA replication, and virus production were only partly rescued. In hamsters, Min AL and derivatives remained highly restricted in replication in the upper and lower airways, but induced serum IgG and IgA responses to the prefusion form of F (pre F) that were comparable to those induced by wt RSV, as well as robust mucosal and systemic IgG and IgA responses against RSV G. Min AL and derivatives were fully protective against challenge virus replication. The derivatives had increased genetic stability compared to Min AL. Thus, Min AL and derivatives with selected mutations are stable, attenuated, yet highly-immunogenic RSV vaccine candidates that are available for further evaluation.

Detailed analysis of low temperature inactivation of respiratory syncytial virus.

Our previous findings indicated that many respiratory syncytial virus (RSV) isolates are unstable at 4 °C compared to 20 °C. Some of the strains completely lose infectivity after 24 h at 4 °C. This study analyzed the inactivation process at 4 °C using a representative strain, RSV/Sendai/851/13. After 24 h of storage at 4 °C, the virus was completely inactivated but retained its ability to attach to and to be taken into host cells. It suggested a reduced fusion ability between the viral and cellular membranes. During storage at 4 °C, the RSV fusion (F) protein underwent a conformational change and was no longer recognized by pre-fusion form-specific antibodies. When the RSV/Sendai/851/13 strain was passaged at 4 °C, a variant with an amino acid substitution, I148T, in the F protein fusion peptide was selected. Also, an amino acid change in G protein demonstrating stability at low temperatures was obtained. These results show that the inactivation of RSV at 4 °C is due to the loss of membrane fusion activity in the F protein, which cannot maintain its pre-fusion state at 4 °C.

Modelling respiratory syncytial virus age-specific risk of hospitalisation in term and preterm infants.

BACKGROUND: Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory infections in children worldwide. The highest incidence of severe disease is in the first 6 months of life, with infants born preterm at greatest risk for severe RSV infections. The licensure of new RSV therapeutics (a long-acting monoclonal antibody and a maternal vaccine) in Europe, USA, UK and most recently in Australia, has driven the need for strategic decision making on the implementation of RSV immunisation programs. Data driven approaches, considering the local RSV epidemiology, are critical to advise on the optimal use of these therapeutics for effective RSV control. METHODS: We developed a dynamic compartmental model of RSV transmission fitted to individually-linked population-based laboratory, perinatal and hospitalisation data for 2000-2012 from metropolitan Western Australia (WA), stratified by age and prior exposure. We account for the differential risk of RSV-hospitalisation in full-term and preterm infants (defined as < 37 weeks gestation). We formulated a function relating age, RSV exposure history, and preterm status to the risk of RSV-hospitalisation given infection. RESULTS: The age-to-risk function shows that risk of hospitalisation, given RSV infection, declines quickly in the first 12 months of life for all infants and is 2.6 times higher in preterm compared with term infants. The hospitalisation risk, given infection, declines to < 10% of the risk at birth by age 7 months for term infants and by 9 months for preterm infants. CONCLUSIONS: The dynamic model, using the age-to-risk function, characterises RSV epidemiology for metropolitan WA and can now be extended to predict the impact of prevention measures. The stratification of the model by preterm status will enable the comparative assessment of potential strategies in the extended model that target this RSV risk group relative to all-population approaches. Furthermore, the age-to-risk function developed in this work has wider relevance to the epidemiological characterisation of RSV.

Adjuvanted Vaccine to Prevent Respiratory Syncytial Virus in Adults Ages 60 Years and Older.

Respiratory syncytial virus (RSV) is a prevalent cause of acute lower respiratory tract illness that disproportionately affects older adults, young children, and infants, which can lead to hospitalizations and death. The health impact on the elderly and infants accentuates the need for effective preventive strategies. Arexvy is the first approved vaccine to prevent lower respiratory tract illness caused by RSV in older adults ages 60 and older. It contains recombinant respiratory syncytial virus glycoprotein F stabilized in the prefusion conformation. Arexvy offers approximately 83% protection in adults and appears to maintain effectiveness for up to two RSV seasons. The vaccine was generally well tolerated in clinical trials, with the most frequently observed and reported adverse events being mild to moderate injection site pain, fatigue, myalgia, headache, and arthralgia. This article includes a description of Arexvy, the target population, contraindications, side effects, and clinical implications when considering the use of this vaccine.

Respiratory Syncytial Virus and Influenza Infections in Children in Ulaanbaatar, Mongolia, 2015-2021.

BACKGROUND: Data available for RSV and influenza infections among children < 2 years in Mongolia are limited. We present data from four districts of Ulaanbaatar from April 2015 to June 2021. METHODS: This study was nested in an enhanced surveillance project evaluating pneumococcal conjugate vaccine (PCV13) impact on the incidence of hospitalized lower respiratory tract infections (LRTIs). Our study was restricted to children aged < 2 years with arterial O2 saturation < 93% and children with radiological pneumonia. Nasopharyngeal (NP) swabs collected at admission were tested for RSV and influenza using qRT-PCR. NP swabs of all patients with radiological pneumonia and of a subset of randomly selected NP swabs were tested for S. pneumoniae (S.p.) by qPCR and for serotypes by culture and DNA microarray. RESULTS: Among 5705 patients, 2113 (37.0%) and 386 (6.8%) had RSV and influenza infections, respectively. Children aged 2-6 months had a higher percentage of very severe RSV infection compared to those older than 6 months (42.2% versus 31.4%, p-value Fisher's exact = 0.001). S.p. carriage was detected in 1073/2281 (47.0%) patients. Among S.p. carriage cases, 363/1073 (33.8%) had S.p. and RSV codetection, and 82/1073 (7.6%) had S.p. and influenza codetection. S.p. codetection with RSV/influenza was not associated with more severe LRTIs, compared to only RSV/influenza cases. CONCLUSION: In Mongolia, RSV is an important pathogen causing more severe LRTI in children under 6 months of age. Codetection of RSV or influenza virus and S.p. was not associated with increased severity.

Respiratory syncytial virus in pediatric patients admitted to a tertiary center in Amman: clinical characteristics, and age-related patterns.

BACKGROUND: Respiratory syncytial virus (RSV) is a common cause of acute lower respiratory tract infections, particularly in infants and young children during winter. We aimed to study the demographics and clinical characteristics of RSV infections and age-related patterns. METHODS: This retrospective study evaluated pediatric respiratory syncytial virus (RSV) infections conducted in Jordan from September 2021 to March 2022. Patients under the age of five who had viral polymerase chain reaction results showing RSV infection from nasopharyngeal aspiration were included. In addition, demographic information, medical history, and clinical data were gathered. These included comorbidities, outcomes, length of stay, ICU hospitalization, use of antibiotics, and oxygen supplementation. RESULTS: A total of 199 patients were included. Most patients were males (56.8%) and less than one year (43.7%). Children aged between 1 and 2 years presented with more shortness of breath (90.1%) than infants and children more than two years (66.7% and 87%, respectively) (p < 0.001). Older children (> 2 years) were significantly more likely to use antibiotics and have ICU admission than younger children ≤ 2 years (p = 0.045 and 0.018, respectively). There was no relationship between age groups, recurrent hospitalization, previous RSV infection, oxygen therapy, coinfection, and hospitalization duration. The respiratory rate was higher among patients with co-infection (p = 0.031). CONCLUSION: The current study provides information on the demographics and clinical characteristics of RSV infections. These findings contribute to a nuanced understanding of RSV infections in the specified population, emphasizing age-specific variations and clinical implications for better management strategies.

Proof of stability of an RSV Controlled Human Infection Model challenge agent.

In 2018, SGS Belgium NV developed RSV-NICA (Respiratory Syncytial Virus-Nasobronchial Infective Challenge Agent), an RSV type A challenge agent for use in RSV Controlled Human Infection Model (CHIM) studies.It is widely recognized that the stability of RSV can be influenced by a variety of environmental parameters, such as temperature and pH. Consequently, our objective was to evaluate the stability of the viral titer of RSV-NICA following five years of controlled storage and to determine the uniformity of the viral titers across different vials of a GMP-qualified batch of RSV-NICA. In addition, we examined the capacity of RSV-NICA to infect human primary airway epithelial cells (MucilAir™), the principal target cells of RSV, and evaluated the influence of single and recurrent freeze-thaw cycles on the infectious viral titer of the challenge agent.The aliquoted RSV-NICA virus stock was subjected to standard virological and molecular methods to gather data on the titer and consistency of the viral titer contained within 24 representative vials of the stock. Our findings illustrate that over a span of five years of cryo-storage, the infectious viral titer in 75% of the tested vials exhibited a comparable average infectious viral titer (4.75 ± 0.06 vs 4.99 ± 0.11; p-value = 0.14). A considerable reduction down to an undetectable level of infectious virus was observed in the remaining vials. RSV-NICA demonstrated its capacity to effectively infect differentiated human airway epithelial cells, with active virus replication detected in these cells through increasing RSV genome copy number over time. Virus tropism for ciliated cells was suggested by the inhibition of cilia beating coupled with an increase in viral RNA titers. No discernable impact on membrane barrier function of the epithelial lung tissues nor cytotoxicity was detected. Pooling of vials with infectious titers > 4.0 log10 TCID50/ml and freeze-thawing of these combined vials showed no deterioration of the infectious titer. Furthermore, pooling and re-aliquoting of vials spanning the entire range of viral titers (including vials with undetectable infectious virus) along with subjecting the vials to three repeated freeze-thaw cycles did not result in a decrease of the infectious titers in the tested vials.Taken together, our findings indicate that long-term cryo-storage of vials containing RSV-NICA challenge agent may influence the infectious viral titer of the virus, leading to a decrease in the homogeneity of this titer throughout the challenge stock. However, our study also demonstrates that when heterogeneity of the infectious titer of an RSV stock is observed, rounds of pooling, re-aliquoting and subsequent re-titration serve as an effective method not only to restore the homogeneity of the infectious titer of an RSV-A stock, but also to optimize patient-safety, scientific and operational aspects of viral inoculation of study participants during at least the period of one RSV CHIM trial. RSV-NICA is a stable, suitable CHIM challenge agent that can be utilized in efficacy trials for RSV vaccines and antiviral entities.

Geographic Progression of Infant Respiratory Syncytial Virus Associated Bronchiolitis Across the United States Before and Since the Onset of COVID-19: Results From Four Health Systems, 2015-2023.

BACKGROUND: Respiratory syncytial virus (RSV) is a substantial cause of infant morbidity and mortality due to seasonal peaks of bronchiolitis across the United States. Clinical and viral surveillance plays a pivotal role in helping hospital systems prepare for expected surges in RSV bronchiolitis. Existing surveillance efforts have shown a geographic pattern of RSV positivity across the United States, with cases typically starting in the southeast and spreading north and west. Public health measures implemented due to the COVID-19 pandemic disrupted viral transmission across the nation and altered the expected seasonality of RSV. The impact of these changes on the geographic progression of infant RSV bronchiolitis across the United States has not been described. METHODS: Here, we used clinical and viral surveillance data from four health care systems located in different regions of the United States to describe the geographic progression of infant RSV bronchiolitis across the country from 2015 to 2023. RESULTS: Prior to widespread circulation of SARS-CoV-2, infant RSV bronchiolitis followed an established geographic pattern associated with seasonal epidemics originating in Florida and spreading north (North Carolina and New York) and later westward (Nevada). Although public health and social measures implemented during the COVID-19 pandemic disrupted the seasonality of RSV disease, infant RSV bronchiolitis epidemics progressed across the nation in a pattern identical to the prepandemic era. CONCLUSIONS: Our findings highlight the importance of ongoing clinical and viral surveillance to optimally track the onset of RSV epidemics and allow health care systems to prepare for expected RSV bronchiolitis surges.

Efficacy, immunogenicity and safety of respiratory syncytial virus prefusion F vaccine: systematic review and meta-analysis.

OBJECTIVE: A notable research gap exists in the systematic review and meta-analysis concerning the efficacy, immunogenicity, and safety of the respiratory syncytial virus (RSV) prefusion F vaccine. METHODS: We conducted a comprehensive search across PubMed, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov to retrieve articles related to the efficacy, immunogenicity, and safety of RSV prefusion F vaccines, published through September 8, 2023. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: A total of 22 randomized controlled trials involving 78,990 participants were included in this systematic review and meta-analysis. The RSV prefusion F vaccine exhibited a vaccine effectiveness of 68% (95% CI: 59-75%) against RSV-associated acute respiratory illness, 70% (95% CI: 60-77%) against medically attended RSV-associated lower respiratory tract illness, and 87% (95% CI: 71-94%) against medically attended severe RSV-associated lower respiratory tract illness. Common reported local adverse reactions following RSV prefusion F vaccination include pain, redness, and swelling at the injection site, and systemic reactions such as fatigue, headache, myalgia, arthralgia, nausea, and chills. CONCLUSIONS: Our meta-analysis suggests that vaccines using the RSV prefusion F protein as antigen exhibit appears broadly acceptable efficacy, immunogenicity, and safety in the population. In particular, it provides high protective efficiency against severe RSV-associated lower respiratory tract disease.

Short- and mid-term morbidity and primary-care burden due to infant respiratory syncytial virus infection: A Spanish 6-year population-based longitudinal study.

BACKGROUND: The morbidity burden of respiratory syncytial virus (RSV) in infants extends beyond hospitalization. Defining the RSV burden before implementing prophylaxis programs is essential for evaluating any potential impact on short- to mid-term morbidity and the utilization of primary healthcare (PHC) and emergency services (ES). We established this reference data using a population-based cohort approach. METHODS: Infants hospitalized for RSV from January 2016 to March 2023 were matched with non-hospitalized ones based on birthdate and sex. We defined the exposure as severe RSV hospitalization. The main study outcomes were as follows: (1) PHC and ES visits for RSV, categorized using the International Classification of Primary Care codes, (2) prescriptions for respiratory airway obstructive disease, and (3) antibacterial prescriptions. Participants were followed up from 30 days before hospitalization for severe RSV until the outcome occurrence or end of the study. Adjusted incidence rate ratios (IRRs) of the outcomes along with their 95% confidence intervals (CI) were estimated using Poisson regression models. Stratified analyses by type of PHC visit (nurse, pediatrician, or pharmacy) and follow-up period were undertaken. We defined mid-term outcomes as those taking place up to 24 months of follow-up period. RESULTS: The study included 6626 children (3313 RSV-hospitalized; 3313 non-hospitalized) with a median follow-up of 53.7 months (IQR = 27.9, 69.4). After a 3-month follow-up, severe RSV was associated with a considerable increase in PHC visits for wheezing/asthma (IRR = 4.31, 95% CI: 3.84-4.84), lower respiratory infections (IRR = 4.91, 95% CI: 4.34-5.58), and bronchiolitis (IRR = 4.68, 95% CI: 2.93-7.65). Severe RSV was also associated with more PHC visits for the pediatrician (IRR = 2.00, 95% CI: 1.96-2.05), nurse (IRR = 1.89, 95% CI: 1.75-1.92), hospital emergency (IRR = 2.39, 95% CI: 2.17-2.63), primary healthcare emergency (IRR: 1.54, 95% CI: 1.31-1.82), as well as with important increase in prescriptions for obstructive airway diseases (IRR = 5.98, 95% CI: 5.43-6.60) and antibacterials (IRR = 4.02, 95% CI: 3.38-4.81). All findings remained substantial until 2 years of post-infection. CONCLUSIONS: Severe RSV infection in infants significantly increases short- to mid-term respiratory morbidity leading to an escalation in healthcare utilization (PHC/ES attendance) and medication prescriptions for up to 2 years afterward. Our approach could be useful in assessing the impact and cost-effectiveness of RSV prevention programs.

Immunogenicity and safety of Ad26.RSV.preF/RSV preF protein vaccine at predicted intermediate- and end-of-shelf-life as an evaluation of potency throughout shelf life.

This study assessed three Ad26.RSV.preF/RSV preF protein combinations, combining different Ad26.RSV.preF doses and naturally aged preF protein, representing the expected critical vaccine quality attributes close to release, around intermediate shelf-life (ISL) and near-presumed end-of-shelf-life (EoSL), as a way to evaluate the vaccine immunogenicity and safety throughout its shelf-life. A single dose of Ad26.RSV.preF/RSV preF protein vaccine was administered to adults 60-75 years of age. Solicited adverse events (AEs), unsolicited AEs, and serious AEs (SAEs) were assessed for 7-day, 28-day, and 6-month periods after vaccination, respectively. RSV preF-binding antibody concentrations and RSV neutralizing titers were measured 14 days post-vaccination as primary and secondary endpoints, respectively; binding antibodies were also measured 6 months post-vaccination. The RSV preF-binding antibody responses induced by Ad26.RSV.preF/RSV preF protein vaccine lots representing the critical quality attributes around ISL and near presumed EoSL were noninferior to the responses induced by the vaccine lot representing the critical quality attributes near release. The RSV preF-binding and RSV neutralizing antibody levels measured 14 days post-vaccination were similar across the 3 groups. RSV preF-binding antibody concentrations were also similar 6 months post-vaccination. Solicited AEs were mostly mild to moderate in intensity, and a decreased reactogenicity was observed from the Release group to the ISL and EoSL group. None of the reported SAEs were considered related to study vaccination. The study provided evidence of sustained immunogenicity and safety over the intended shelf-life of the Ad26.RSV.pref/RSV preF protein vaccine. The three vaccine lots had acceptable safety profiles.